The Characterization of the Vertical Sidewall MOSFETs with Smart Body-tie, Buried Block Layer, and Novel Embedded Gate

by Lee, Tai-yi

Abstract (Summary)
In this thesis, according to the development of the vertical MOSFETs, we propose several MOSFETs that possess vertical channels, double gates, and buried oxide to solve the defects of the applications in switch devices, CMOS technique, and power devices. The vertical sidewall MOSFETs has many advantages, such as the packing density improvement, multiple channels, and independence on the critical lithography. Based on these characteristics, three kinds MOSFETs are now proposed. The first one is the vertical SOI MOSFET with smart source/ body contact (SSBVMOS). It is proposed to solve the floating body effect and self-heating effect. SSBVMOS provides a body-tie that does not occupy the excessive wafer area. It uses the smart source/body-tie to eliminate the unnecessary carriers and to provide an effective heat pass way. In addition, SSBVMOS is discussed with respect to the channel length and the buried oxide thickness adjustments, and also compared with the conventional vertical sidewall MOSFETs. The second one is the vertical MOSFET with upper and internal l-shape buried oxide (ULVMOS). ULVMOS uses the buried oxide to decrease the junction leakage. The ULVMOS also operates under the fully depleted regime to provide good characteristics. The last one is the novel embedded vertical sidewall MOSFETs (EGVMOS). EGVMOS maintains the advantages of the vertical structures and reduces the fabrication difficulty. It is also expected to decrease the overlap capacitance issue which affects the AC performance in the vertical sidewall MOSFET. As semiconductor channel length scaled down, the proposed devices is proved to provide effective applications for achieving good subthreshold swing, high on-off current ratio, and low DIBL through ISE-TCAD software simulation and real fabrication.
Bibliographical Information:

Advisor:Jyi-tsong Lin; none; none; none; none

School:National Sun Yat-Sen University

School Location:China - Taiwan

Source Type:Master's Thesis

Keywords:floating body kink


Date of Publication:06/27/2008

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